Atomic Structure and the Periodic Table Flashcards
What are atoms made up of?
Protons, neutrons and electrons
Give the relative mass and relative charge of each subatomic particle?
Particle | Mass | Charge
Proton | 1 | +1
Neutron | 1 | 0
Electron | 1/1840 | -1
What is the relative isotopic mass?
The mass of an atom of an isotope comapred with 1/12th the mass of a carbon-12 atom. RIM is an isotopes mass number
What is the relative atomic mass?
The ratio of the average mass of an atom of an element to 1/12th of the mass of an atom of carbon-12
What is relative molecular mass?
The ratio of the average mass of a molecule of an element or compount to 1/12th of the mass of an atom of carbon-12
What is relative molecular mass?
The ratio of the average mass of a molecule of an element or compount to 1/12th of the mass of an atom of carbon-12
What is relative molecular mass?
The ratio of the average mass of a molecule of an element or compound to 1/12th of the mass of an atom of carbon-12
What is the relative formula mass?
The average mass of a formula unit of a substance, relative to 1/12th the mass of a carbon-12 atom.
What is the mass number of an element? How is it represented?
A - The total number of protons and neutrons in the nucleus
What is the atomic (proton) number of an element? How is it represented?
Z - The total number of protons in the nucleus
What is an isotope?
Atoms with the same number of protons and different numbers of neutrons.
Describe the process of mass spectrometry.
Vapourisation - turning the sample into a vapour
Ionisation - an electron gun is used to displace electrons from all the vapourised atoms which gives them all a 1+ charge
Acceleration - charged atoms are accelerated in an electric field
Deflection - a magnetic field is used to deflect the charged atoms; the amount a particle is deflected depends on its mass
Detector - particles with less deflection have a higher mass
What can you determine from the data produced in mass spectrometry of a sample?
You can find the relative abundances of different isotopes on an element. RMM of each species in a sample is shown on the x axis. Relative atomic mass can also be calculated from the data, using relative isotopic masses and abundances.
What are the four types of orbitals and how many electrons it can hold? (In order of ascending electron capacity)
s-2,p-6,d-10,f-14
What is meant by the term orbital?
A region of space within an atom that can hold up to two electrons with opposite spins
Describe an explain existing evidence for the existence of quantum shells and sub-shells.
Atomic emission spectra and successive ionisation energies prove the existence of quantum shells.
First ionisation energy of sucessive elements proves the exisence of electron sub-shells
What are the three rules that are used when filling shells and sub-shells with electrons?
Afubau’s rule - fill shells from lowest to highest energy (4s is lower than 3d)
Pauli’s rule - electrons in the same orbital must have opposite spin
Hund’s rule - fill orbitals in the same group individually before pairing
What are the two exceptions to Afubau’s rule of filling lower energy shells first?
Copper and chromium should only have one electron in the 4s orbital, not 2 and then other electron goes into the 3d orbital.
Define first ionisation energy.
Energy required to
remove 1 electron each from
1 mole of gaseous atoms
Define second ionisation energy.
Energy required to
remove 1 electron each from
1 mole of gaseous 1+ ions.
Write an equation to represent the first ionisation energy.
C(g) -> C+(g) + e-
Write an equation to represent the second ionisation energy.
C+(g) -> C 2+(g) + e-
What factors affect the ionsation energy of an atom? How do they affect it?
Nuclear charge - more charge, more energy required
Distance and shielding from nucleus - greater distance/shielding, less energy required
If the outermost electron is sharing an orbital - ?
Describe and explain the change in ionisation energy across a period.
IE increases due to:
- increasing nuclear charge
- attraction to nucleus increases
NB.
- distance + shielding remains relatively constant
Describe and explain the cahnge in first ionisation energy down a group.
First IE decreases down the group:
- despite the increase in nuclear charge
- distance/shielding increases more significantly
- overall decreasing the attraction to the nucleus
Describe and explain the trend of atomic radii across different periods.
Down group:
- increases as more shells of electrons fill
Across period:
- decreases (despite increase in no. of e-) due to increasing nuclear charge
Describe and explain the trend of ionic charge across different periods.
Metals loose e-
Non-metals gain e-
Ionic charge depends on group.
Describe and explain the trend of ionic radii across different periods.
Increase down the group due to increasing no. of shells of electrons.
Decrease across period as ions isoelectronic with an increasing nuclear charge.
Describe and explain the trend of structure and bonding across different periods.
Group 8/0 - monatomic
Metals (G1-3) - giant : metallic
Non-metals (G4) - giant : covalent
Non-metals (G5-7) - simple : covalent
Describe and explain the trend of electrical confuctivity across different periods.
Metals have delocalise electrons in pure structure which can conduct a current.
All others have no available charge carriers (electrons) in pure structure.
Define periodicity.
Trends in properties of elements (and their atoms) repeat in successive periods of the periodic table.
